A communication disorder is a disease or condition that partially or totally prevents human communication. The defect can be in producing, receiving or understanding the communication.
Examples of communication disorders:
autism -- a developmental defect that affects understanding of emotional communication
aphasia -- loss of the ability to produce or comprehend language
... out with 29.0% under the age of 18, 5.0% from 18 to 24, 29.0% from 25 to 44, 24.2% from 45 to 64, and 12.7% who are 65 years of age or older. The median age is 39 ...